1. Field of the Invention
The present invention relates to an attachment for an endoscope and an endoscope system, and more particularly, to an attachment for an endoscope and an endoscope system that are used for an endoscope in which a constant-pressure gas is supplied from a gas supply apparatus into a lumen of a subject via an opening provided in a leading end part of a flexible endoscope inserted into the lumen, to thereby perform observation and treatment of the inside of the lumen.
2. Description of the Related Art
Up to now, in medical fields, a medical diagnosis utilizing an endoscope is widely performed. In particular, an image-pickup element such as a CCD is built in an insertion leading end part of the endoscope inserted into a body cavity, and an image inside of the body cavity is photographed by the built-in image-pickup element. The image is subjected to signal processing by a processor apparatus to be displayed on a monitor. A doctor observes for a diagnosis the processed image. Otherwise, a treatment tool is inserted from a channel for treatment tool insertion, to thereby perform treatment, for example, collection of a sample and excision of a polyp.
In particular, a flexible insertion part of a flexible endoscope is inserted into a lumen of a stomach, a large intestine, or other organs, and diagnosis and treatment are performed on the inside of the lumen. In this case, a treatment tool is inserted into the lumen via a forceps channel (treatment tool channel) of the flexible endoscope, to thereby perform the curative treatment.
At this time, in order to secure the field of view of the flexible endoscope and secure space for operating the treatment tool, a constant-pressure supplied gas such as carbon dioxide gas is supplied into the lumen for the purpose of inflating the lumen.
For example, Japanese Patent Application Laid-Open No. 2009-106360 discloses a laparoscope-assisted surgery system including two endoscopes, that is, a rigid endoscope and a flexible endoscope, in which: a plurality of trocars are inserted into an abdomen of a patient; the rigid endoscope is inserted into an abdominal cavity from one of the trocars; an insufflation gas supplied from an insufflation apparatus is guided into the abdominal cavity via the other trocars; and the flexible endoscope is further inserted into a lumen of a large intestine or other organs. Then, in this system, carbon dioxide gas, which is adjusted to a predetermined pressure, is guided into the abdominal cavity via the other trocars and carbon dioxide gas is also supplied into the lumen via a treatment tool channel of the flexible endoscope, as the insufflation gas from the insufflation apparatus.
Unfortunately, in the case as in the above-mentioned conventional example where a constant-pressure gas is supplied via an opening of the treatment tool channel, such as a forceps port, formed in a leading end part of the flexible endoscope, bubbles are generated near a gas jetting port by a bodily fluid or water attached to a leading end surface of the endoscope, and the bubbles are attached to an observation window (image-pickup apparatus) formed on the leading end surface, so that the field of view is blocked unfavorably.